1. Field of the Invention
The present invention relates to a structure for the rear section of a vehicle body, and, more particular, to a rear body structure for a vehicle which provides an improved rigidity of rear suspension towers.
2. Description of Related Art
Typically, in a body structure of the rear section of an automotive vehicle, right and left shock absorbers are installed on both sides of the vehicle body so that the distance between axes of these shock absorbers widens toward their lower ends as viewed in a lengthwise direction of the vehicle body, which attributes to the arrangement of right and left rear suspensions. Such a rear body structure makes a rear suspension tower tend to easily fall sideways towards the compartment with a thrust-up force from the shock absorber. Conventionally, in order to prevent the rear suspension tower from falling sideways, the rear suspension tower is provided with a gusset which is located inside the rear body or in the rear compartment of the vehicle and interconnects the front ends of the right and left rear suspension tower and a floor panel so as to increase the structural rigidity of the right and left rear suspension tower against sideways fall. Such a rear body structure is known from, for instance, Japanese Unexamined Utility Model Publication No. 63-69679. Otherwise, as is known from, for instance, Japanese Unexamined Utility Model Publication No. 62-200077, a rear body structure is provided with what is called a "package tray or upper back panel," which is placed above and between the right and left rear suspension towers so as to extend backward from a rear compartment and is bolted to the right and left rear suspension towers, and a reinforcement. These package tray and reinforcement are joined so as to form a closed cross-sectional hollow structure extending sideways from each rear suspension tower.
In the rear body structure provided with a gusset extending sideways from the rear suspension tower, a distance or interval. between fulcrums of the right and left rear suspension towers at which the gussets are connected is concerned in the effective prevention of sideways fall of the rear suspensions. Nevertheless, the rear body structure only provides a transverse width of the gusset for the distance between fulcrums at the greatest, and has only an structural rigidity insufficient for sideways fall, in some cases, due to thrust-up force exerted to the rear suspension tower from a shock absorber.
On the other hand, the rear body structure formed with a closed cross section by a gusset extending sideways from the rear suspension tower provides a sufficient distance between fulcrums. However, since the top ends of the right and left rear suspension towers are interconnected by means of a hollow structure having a closed cross section, if the right and left rear suspension towers are subjected to uneven thrust-up force from the right and left shock absorbers, they cause a relative twist therebetween.